Stay-bolt for boilers.



E. l. DODDS.

STAY BO'LT FOR BQILERS.

APPLICATION FILED NOV. 30. 1914.

Patented June 27, 1916.

. THB OOLUABIA PLANOGDAPH o0.. WASHINGTQN. D. C.

Fi"` SATES ANT FFIQI.

ETI-IAN I. DODDS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO FLANNERY BOLTl COMPANY, OF PITTSBURGH, PENNSYLVANIA.

' STAY-BOLT ron BoILERs.

Specification of Letters Patent.

Patented June 27, 1916.

Application filed November 30, 1914; Serial Nn. 874,822.

To all whom t may concern.'

Be it known that I, ETHAN I. DoDDs, a citizen of the United States, anda resident of Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inStay-Bolts for Boilers; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates to an improvement in stay bolts for boilers, theobject being to provide a bolt that will be flexible adjacent one orboth heads of the bolt, so that it may accommodate itself to the lateraltwisting -or torsional strains imparted to it by the unequal movementsof the boiler sheets, but which will be sufficiently rigid againstlongitudinal stresses to prevent any buckling or bending of the shankWhile the bolt is being applied to the sheets.

Vith this object in view my invention consists in the details ofconstruction as will be more fully explained and pointed out in theclaims.

In the accompanying drawings, Figure l is view in side elevation partlyin section of a bolt embodying my invention; Figs. 2, 3, and laresections of the same; F ig. 5 is a view showing the bolt shank twisted;Figs. G and 7 are views in elevation partly in section of a modiiiedform of bolt; Figs. 8, 9 and 10 are views in transverse section of thesame; Fig. 11 is a view showing the shank of same twisted; Fig. 12 is aview in section partly in elevation of another form and Figs. 13, 14Cand 15 are views in transverse section of the same.

In the manufacture of this bolt, a bar of stay bolt metal is reducedbetween its heads 1 and 1fL to form the shank of the bolt, and thisshank is slotted at diametrically opposite sides as at 2 and 3, the saidslots starting from the surface at the end of the shank adjacent thehead la, and gradually increasing in depth toward the head 1, andpreferably coming together adjacent said head 1, so that the point ofgreatest flexibility will be localized at the end of the shank adjacentthe head 1. After the shank has been slotted, the slots are closed byhammering or between dies, without welding the walls of the slots, afterwhich the heads 1 and 1a are formed; the tell-taleholeboredinhead l, andthe shank twisted about 180o as shown 1n Fig. 5, so as to carry the slotspirally around the shank.

0 In the construction shown in Figs. 6 to l1 incluslve, the slots areduplicated, and located 90O apart instead of 180o as in Fig. 1, theslots 2 and 3 being deeper adjacent the head l, and the other pair ofslots 2a-3 being deeper adjacent the head la, thus rendering the shankequally fiexible adjacent both heads.

In the construction shown in Figs. l2 to 15 inclusive, a single pair ofoppositely disposed slots 2b and 3 are employed. These slots extend fromone head to the other and are deeper at the ends and shallower at thecenter as shown in Fig. 12. In order to reduce the rigidity of thecentral portion of the bolt I prefer to slot it centrally as at 5.

In all instances, the shank of the bolt is twisted-as shown in Fig. 5 soas to impart a 'spiral form to the slots.

`By weakening the bolt adjacent one or both heads .sufficientflexibility is provided, to permit of a comparatively free movement ofthe sheets to which the bolt is attached without unduly straining eithersheet. It also localizes the strains to the part of the bolt containingthe telltale, so that if the bolt does break, it will do so at the endcontaining the tell-tale and thus permit the escape of steam or water toindicate and locate the break.

The slots above referred to are formed by cutting or piercing the metal7instead of punching so that the capacity of the shank for endwisestresses is not weakened.

Having fully described my invention what I claim as new and desire tosecure by Letters-Patent, is

1. As a new article of manufacture, a bolt having a head and a shank,the latter having oppositely disposed slots which are deepest adjacentthe head.

2. As a new article of manufacture a bolt having a head and a shank thelatter having oppositely disposed slots which are deepest adjacent thehead, the said shank being twisted to impart spiral form to the slots.

3. As a new article of manufacture, a bolt having two heads and anintermediate shank, the latter having two pairs of oppo- In testimonywhereof, I have signed this' sitely disposed slots, one pair of slotsbeing speeication in the-'presence of tWo subscribdeepest adjacent onehead and merging into ing Witnesses.

the surface of the bolt near the other head ETHAN I. DODDS.- and theother pair being Vdeepest adjacent Witnesses:

- the opposite head and merging into the sur- WM. CHARLES BINGHAM,

face of the shank near the other head. EDWIN SPENCER RYCE.

Copies of this patent may he obtained for ve cents each, by addressing'the Commissioner of Patents, Washington, D. C.

